I am working on PS and I have a couple of questions.
1) If 24 amperes of current flows through an appliance connected to a 120-volt circuit what is the resistance of the appliance.
A).22 ohms
b)5 ohms
c)50 ohms
d)2880 ohms
I am not sure how to go about figuring that one out
2)If you doubled both the voltage and the resistence in a circuit what would be the effect on the current?
a)the current would increase by 4 times
b)the current would be doubled
c)the current would stay the same
d)the current would decrease 1/4
I think the answer is C
3)when there is a change in the magnetic field in a closed loop of wire.
a)electromagnetic induction occurs
b)a voltage is induced in the wire
c)current is made to flow in the loop of wire.
d)all of the above
I think is is A or possibly D
4)power is transmitted at high voltages because the corresponding current in the wires is?
a)also high to deliver appreciable power to distant places
b)low so that overheating of the wires is minimized.
c)both a and b
d)neither a nor b
I think it is A
5)when a magnet is pushed back and forth 1 time per second through a coil of wire made of 10 loops it produces 10 amperes of current. If we want to make it produce 100 amperes what should we do?
a)move the magnet back and forth more slowly about once every 10 seconds
b)increase the number of loops to 100 and push at the same rate
c)decrease the number of loops to only one loop and move at the same rate
d)decrease the coils to 5 coils and inscrease the motion to twice as fast.
I really have no idea on this one, and can't find anything about it in the book or online.
Thanks so much for the help
R=V/I.
So #1 is B 5?
5. Magnetic induction is proprotional to number of turns, and frequency.
4. Nonsense. Power= V*I
3. It is not A or D, it is one of them.
2. correct.
If R=V/I,then 120V/24A=?It does not get much easier!Try a calculator.
1) To find the resistance of the appliance, you can use Ohm's Law. Ohm's Law states that resistance (R) is equal to voltage (V) divided by current (I), or R = V/I. In this case, the voltage is given as 120 volts and the current is given as 24 amperes. So you can calculate the resistance by dividing 120 volts by 24 amperes. The answer will be in ohms.
R = V/I = 120V/24A = 5 ohms
Therefore, the resistance of the appliance is 5 ohms. So the correct answer is b) 5 ohms.
2) If you double both the voltage and the resistance in a circuit, the effect on the current can be determined by applying Ohm's Law. Ohm's Law states that current (I) is equal to voltage (V) divided by resistance (R), or I = V/R. Since the resistance is doubled, the current will decrease. Let's go through the options:
a) The current would increase by 4 times - This is not correct because doubling the voltage and resistance does not result in a fourfold increase in current.
b) The current would be doubled - This is not correct because doubling the voltage and resistance does not result in a twofold increase in current.
c) The current would stay the same - This is not correct because doubling the resistance would cause the current to decrease.
d) The current would decrease 1/4 - This is the correct answer. Doubling the resistance would result in the current decreasing by a factor of 1/4, or 25%.
Therefore, the correct answer is d) the current would decrease 1/4.
3) When there is a change in the magnetic field in a closed loop of wire, several things occur. Let's go through the options:
a) Electromagnetic induction occurs - This is true. When there is a change in the magnetic field, electromagnetic induction occurs, which is the process by which a voltage is induced in the wire.
b) A voltage is induced in the wire - This is true. As mentioned above, electromagnetic induction results in the induction of a voltage in the wire.
c) Current is made to flow in the loop of wire - This is true. The induced voltage in the wire causes current to flow in the loop of wire.
d) All of the above - This is the correct answer. All of the statements in options a), b), and c) are true when there is a change in the magnetic field in a closed loop of wire.
Therefore, the correct answer is d) all of the above.
4) Power is transmitted at high voltages because the corresponding current in the wires is lower, which helps minimize overheating of the wires. Electric power is given by the equation P = VI, where P is power, V is voltage, and I is current. Let's go through the options:
a) Also high to deliver appreciable power to distant places - This is not correct. Transmitting power at high voltages allows for lower currents, which helps minimize the loss of power in transmission lines and reduces the heating effect.
b) Low so that overheating of the wires is minimized - This is correct. Transmitting power at high voltages results in lower currents, which reduces the heating effect and minimizes the risk of overheating the wires.
c) Both a and b - This is not correct. It is actually only option b) that is correct.
d) Neither a nor b - This is not correct. Option b) is correct.
Therefore, the correct answer is b) low so that overheating of the wires is minimized.
5) To produce 100 amperes of current in the coil of wire, you can manipulate the factors that affect magnetic induction. Remember that magnetic induction is proportional to the number of turns and the frequency. Let's go through the options:
a) Move the magnet back and forth more slowly about once every 10 seconds - This is not correct. Slowing down the motion of the magnet would decrease the frequency, which would result in a decrease in the induced current.
b) Increase the number of loops to 100 and push at the same rate - This is not correct. Increasing the number of loops would increase the magnetic induction, but it would not be enough to produce 100 amperes of current.
c) Decrease the number of loops to only one loop and move at the same rate - This is not correct. Decreasing the number of loops would decrease the magnetic induction, resulting in a decrease in the induced current.
d) Decrease the coils to 5 coils and increase the motion to twice as fast - This is the correct answer. Decreasing the number of coils to 5 would decrease the magnetic induction, but increasing the motion to twice as fast would increase the frequency, resulting in a higher induced current. This combination could potentially produce 100 amperes of current.
Therefore, the correct answer is d) decrease the coils to 5 coils and increase the motion to twice as fast.
I hope this helps! Let me know if you have any further questions.